Extension plank



Nov. 26, 1929 D MacDQNALD 1,737,315

EXTENSION PLANK Filed Dec. '10, 1927 17 17 Dawn/d L7. MacDunD/dI'nvE'nfmY ing the bolt G therethrough.

Patented Nov. 26, 1929 s'rrs UNITE DONALD J. MACDONALD, OF CAMBRIDGE,MASSACHUSETTS EXTENSION PLANK Application filed December 10, 1927.Serial No. 239,122.

My invention relates to extension planks of the type adaptable for useby painters or other mechanics in building or repair work. It has forits purpose to provide a plank adjustable to varying lengths forconvenience in use or shipping; to provide a graduated lap jointdesigned to avoid stumbling; to provide a simple and effective lockingmeans designed to prevent slipping in use; to pro- 1 vide a hinge andswinging bolt construction designed to hold bolts from turning and tofacilitate ease in dismounting; and to pro- Vide the various otheradvantages and results made evident from the following specification.

I accomplish the objects of my invention as shown in the accompanyingdrawings which form a part of this specification and in which Figure 1shows my assembled plank in position for use. Figure 2 shows a sectionalview on the line A-A in Figure 1. Figure 3 shows a detailed side View ofmy channel unit. Figure 3 shows a detailed plan View of my channel unit.Figure 4 shows a I plan View of the base unit. Figure 5 shows a top viewof my assembled plank.

Referring again to the drawings B and C designate the respective plankunits, the ends of which slide within the channel units comprising theparallel bars D and E. The tops of the channel bars are deslgnated D Thesides are designated D and D The end of side 1) is bifurcated as shownin Figure 3 and the arms thereof are bentto form spaced eyes D Thehinges are designated D The base fingers are designated E and E. Theswinging bolts are designated as D and are pivoted on crosspins Dcarried in the eyes D The tightening nuts are designated as D. A seriesof orifices F in the plank units B and C are positioned so that twothereof may register when the planks B and O are at designatedextensions, and when so registered a locking in fixed position issecured by pass- While I have illustrated and described a preferredconstruction for carrying my nvention into effect, this is capable ofvariatlon or modification without departing from the spirit of theinvention. I therefore do not wish to be limited to the exact detailsof. construction herein set forth but desire to avail myself of suchvariations and modifications as come within the scope of the appendedclaims.

Having thus described my invention I claim as new and desire to secureby Letters Patent of the United States of America p 1. An extensiondevice comprising a pair of superposed planks overlapping throughout aportion of their lengths and slidable longitudinally with respect toeach other to increase the ovcr-all length of the device, said plankshaving registering openings for receiving positive and removablesecuring means therethrough, and the overlapping portions of said planksbeing received in spaced keepers, each of which engages about the uppersurface of the top plank and down across the edges of both planks toholdthe planks in registry one above the other, and each keeper having ahinged clamping member extending across the bottom surface of the lowerplank to clamp the planks together and retain them in the keepers.

2. A keeper for clamping extension planks together, comprising a pair ofhingedly connected members, one of said members being substantiallyusshaped and having its ends bent substantially at right angles to thebody portion and extending in the same direction to engage over and downthe sides of a pair of superposed planks, the ends of said U- shapedmember being bifurcated and the arms of the bifurcations being bentupwardly to form pair of eyes at the ends, another mem ber having an eyeat one end bolted to form a hinge connection with the eyes on one end ofthe first named member, a swivel bolt carried by the eyes in the otherend of the first named member, and the last named memher having abifurcated end engaged by the swivel bolt to clamp planks between saidmembers when the bolt is taken up. In testimony whereof I aflix mysignature.

DONALD J. MACDONALD.

